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An ionized accretion disc wind in Hercules X-1
Fabian, A. C.; Reynolds, C. S.; Pinto, C. +3 more
Hercules X-1 is one of the best-studied highly magnetized neutron star X-ray binaries with a wealth of archival data. We present the discovery of an ionized wind in its X-ray spectrum when the source is in the high state. The wind detection is statistically significant in most of the XMM-Newton observations, with velocities ranging from 200 to 100…
NGTS and WASP photometric recovery of a single-transit candidate from TESS
Hellier, Coel; Jackman, James A. G.; Wheatley, Peter J. +26 more
The Transiting Exoplanet Survey Satellite (TESS) produces a large number of single-transit event candidates, since the mission monitors most stars for only ∼27 d. Such candidates correspond to long-period planets or eclipsing binaries. Using the TESS Sector 1 full-frame images, we identified a 7750 ppm single-transit event with a duration of 7 h a…
Galaxy spin direction distribution in HST and SDSS show similar large-scale asymmetry
Shamir, Lior
Several recent observations using large data sets of galaxies showed non-random distribution of the spin directions of spiral galaxies, even when the galaxies are too far from each other to have gravitational interaction. Here, a data set of$\sim8.7\cdot10^3$spiral galaxies imaged byHubble Space Telescope(HST) is used to test and profile a possibl…
MCMCI: A code to fully characterise an exoplanetary system
Bonfanti, A.; Gillon, M.
Context. Useful information can be retrieved by analysing the transit light curve of a planet-hosting star or induced radial velocity oscillations. However, inferring the physical parameters of the planet, such as mass, size, and semi-major axis, requires preliminary knowledge of some parameters of the host star, especially its mass or radius, whi…
Extinction in the 11.2 µm PAH band and the low L11.2/LIR in ULIRGs
Pérez-González, Pablo G.; Arribas, Santiago; Alonso-Herrero, Almudena +9 more
We present a method for recovering the intrinsic (extinction-corrected) luminosity of the 11.2 µm PAH band in galaxy spectra. Using 105 high S/N Spitzer/IRS spectra of star-forming galaxies, we show that the equivalent width ratio of the 12.7 and 11.2 µm PAH bands is independent on the optical depth (τ), with small dispersion (∼5 per c…
Turbulence and Energetic Particles in Radiative Shock Waves in the Cygnus Loop. II. Development of Postshock Turbulence
Blair, William P.; Slavin, Jonathan D.; Raymond, John C. +3 more
Radiative shock waves in the Cygnus Loop and other supernova remnants show different morphologies in [O III] and Hα emission. We use HST spectra and narrowband images to study the development of turbulence in the cooling region behind a shock on the west limb of the Cygnus Loop. We refine our earlier estimates of shock parameters that were based u…
Heavy-metal enrichment of intermediate He-sdOB stars: the pulsators Feige 46 and LS IV-14°116 revisited
Heber, U.; Latour, M.; Irrgang, A. +3 more
Hot subdwarf stars of spectral types O and B represent a poorly understood phase in the evolution of low-mass stars, in particular of close compact binaries. A variety of phenomena are observed, which make them important tools for several astronomical disciplines. For instance, the richness of oscillations of many subdwarfs are important for aster…
Eigengalaxies: describing galaxy morphology using principal components in image space
Kaviraj, Sugata; Geach, James E.; Uzeirbegovic, Emir
We demonstrate how galaxy morphologies can be represented by weighted sums of 'eigengalaxies' and how eigengalaxies can be used in a probabilistic framework to enable principled and simplified approaches in a variety of applications. Eigengalaxies can be derived from a Principal Component Analysis (PCA) of sets of single- or multiband images. They…
Processes governing the VIS/NIR spectral reflectance behavior of lunar swirls
Wöhler, C.; Grumpe, A.; Bhatt, M. +5 more
We investigated six bright swirls associated with magnetic anomalies of variable strength using Chandrayaan-1 Moon Mineralogy Mapper (M3) hyperspectral image data. We examined the 3 µm absorption band generally ascribed to solar wind-induced OH/H2O and spectral trends in the near-infrared wavelength range at on-swirl an…
Numerical Modeling of Suprathermal Electron Transport in the Solar Wind: Effects of Whistler Turbulence
Zank, Gary P.; Tang, Bofeng; Kolobov, Vladimir I.
The solar wind electron velocity distribution function deviates significantly from an equilibrium Maxwellian distribution and is composed of a Maxwellian core, a suprathermal halo, a field-aligned component strahl, and a higher-energy superhalo. Wave-particle interactions associated with whistler wave turbulence are introduced into the kinetic tra…